blktrace: use cpu_clock() instead of sched_clock() (7c2ff389) · Commits · 戴 / test

block/blktrace.c

+10 −10

Original line number	Diff line number	Diff line
		@@ -41,7 +41,7 @@ static void trace_note(struct blk_trace *bt, pid_t pid, int action,
		const int cpu = smp_processor_id();

		t->magic = BLK_IO_TRACE_MAGIC \| BLK_IO_TRACE_VERSION;
		t->time = sched_clock() - per_cpu(blk_trace_cpu_offset, cpu);
		t->time = cpu_clock(cpu) - per_cpu(blk_trace_cpu_offset, cpu);
		t->device = bt->dev;
		t->action = action;
		t->pid = pid;
		@@ -159,7 +159,7 @@ void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,

		t->magic = BLK_IO_TRACE_MAGIC \| BLK_IO_TRACE_VERSION;
		t->sequence = ++(*sequence);
		t->time = sched_clock() - per_cpu(blk_trace_cpu_offset, cpu);
		t->time = cpu_clock(cpu) - per_cpu(blk_trace_cpu_offset, cpu);
		t->sector = sector;
		t->bytes = bytes;
		t->action = what;
		@@ -488,17 +488,17 @@ void blk_trace_shutdown(struct request_queue *q)
		}

		/*
		* Average offset over two calls to sched_clock() with a gettimeofday()
		* Average offset over two calls to cpu_clock() with a gettimeofday()
		* in the middle
		*/
		static void blk_check_time(unsigned long long *t)
		static void blk_check_time(unsigned long long *t, int this_cpu)
		{
		unsigned long long a, b;
		struct timeval tv;

		a = sched_clock();
		a = cpu_clock(this_cpu);
		do_gettimeofday(&tv);
		b = sched_clock();
		b = cpu_clock(this_cpu);

		t = tv.tv_sec 1000000000 + tv.tv_usec * 1000;
		*t -= (a + b) / 2;
		@@ -510,16 +510,16 @@ static void blk_check_time(unsigned long long *t)
		static void blk_trace_check_cpu_time(void *data)
		{
		unsigned long long *t;
		int cpu = get_cpu();
		int this_cpu = get_cpu();

		t = &per_cpu(blk_trace_cpu_offset, cpu);
		t = &per_cpu(blk_trace_cpu_offset, this_cpu);

		/*
		* Just call it twice, hopefully the second call will be cache hot
		* and a little more precise
		*/
		blk_check_time(t);
		blk_check_time(t);
		blk_check_time(t, this_cpu);
		blk_check_time(t, this_cpu);

		put_cpu();
		}

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